Scalable images

One of the key reasons for the success of the Web are images.

But images do not scale currently very well to mobile devices. A server needs to know the screen size of the mobile device (close to impossible) and then CPU intensively resize it.

SVG will not solve the problem. It is for vector graphics, not for bitmaps!

So I had an idea inspired by watching progressive JPEGs load in the past. Don’t see much of this anymore, perhaps because my Internet connection is so fast.

Wouldn’t it be good enough if just the first few bytes of an image for the UA to generate an increasingly detailed image(resampling on-the-fly)? That way if the resolution limit is reached, it just stops downloading the image. This would also save network bandwidth!

I posted about it on w3-di and PNG implement.

John Bowler offered an encouraging reply. It was Adam Costello who pointed out JPEG2000’s (.jp2) scalability features.

Wow. So JPEG2000 is an ISO standard and royalty free too (although with a history of resolved legal and licensing issues). And a Mozilla bug going back as far as the year 2000. The comments are worth reading. So I’ve voted for bug #36351, but does it really solve the problem?

John Bowler says that JPEG2000’s handling of RGB values are not properly accounted for at different resolutions, which will result in perception errors. Note point 6 and 7 of Blinn’s unsolved image problems.

The PNG-implement thread and its techy details are archived here without a Web interface. (Wishlist: I need a little tool to dump email threads from mutt to a nice Web interface and URL on my server).

I’ll conclude by re-iterating the need to address BITMAP graphics formats and their problems especially for allowing small screen devices efficient access to the Web’s images.

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